ISO 2009 (and its withdrawn predecessor DIN 963) is the standard for slotted countersunk screws/bolts.
It consists of 113 unique sizes from M1.6 to M10 and comes in three materials. The latest revision is from 2011, which you can purchase from ISO here.
One-time investment. No maintenance fees.
113 sizes * 3 materials
= 339 files
European engineers are fond of DIN standards, buy many DIN standards for fasteners were withdrawn in 1992. Most of them have an ISO replacement.
We only offer fasteners for active standards because we purchase the standard document and use it as a source for our fastener models.
Lock and spring washers like DIN 125 and DIN 6798 have been withdrawn without an ISO replacement, most likely because they don't work well.
We were tired of scrolling through endless lists of fasteners in SOLIDWORKS, so we built Lightning. Lightning makes it easy to add, edit and replace fasteners.
Just open the filter, pick a type, size and material, then drag the file into your assembly. Lightning will add a washer and/or a pattern for you.